X-Git-Url: https://git.netwichtig.de/gitweb/?a=blobdiff_plain;f=src%2Fsrc%2Ftls-gnu.c;h=d54c560f708ee9d4d6fd0458a9ee10c2c71a52a3;hb=4c0a7a9cb02f9904c2e890f77ff8ce3a6beb25f4;hp=8391914b6bf97f3fd897e9134a73663272ebaecd;hpb=b34fc30c7704c469a25b5a933fc38867f5128630;p=user%2Fhenk%2Fcode%2Fexim.git diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index 8391914b6..d54c560f7 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -2,7 +2,7 @@ * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge 1995 - 2012 */ +/* Copyright (c) University of Cambridge 1995 - 2015 */ /* See the file NOTICE for conditions of use and distribution. */ /* Copyright (c) Phil Pennock 2012 */ @@ -13,7 +13,7 @@ tls.c when USE_GNUTLS has been set. The code herein is a revamp of GnuTLS integration using the current APIs; the original tls-gnu.c was based on a patch which was contributed by Nikos -Mavroyanopoulos. The revamp is partially a rewrite, partially cut&paste as +Mavrogiannopoulos. The revamp is partially a rewrite, partially cut&paste as appropriate. APIs current as of GnuTLS 2.12.18; note that the GnuTLS manual is for GnuTLS 3, @@ -39,6 +39,34 @@ require current GnuTLS, then we'll drop support for the ancient libraries). #include /* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */ #include +/* needed to disable PKCS11 autoload unless requested */ +#if GNUTLS_VERSION_NUMBER >= 0x020c00 +# include +# define SUPPORT_PARAM_TO_PK_BITS +#endif +#if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP) +# warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile" +# define DISABLE_OCSP +#endif +#if GNUTLS_VERSION_NUMBER < 0x020a00 && !defined(DISABLE_EVENT) +# warning "GnuTLS library version too old; tls:cert event unsupported" +# define DISABLE_EVENT +#endif +#if GNUTLS_VERSION_NUMBER >= 0x030306 +# define SUPPORT_CA_DIR +#else +# undef SUPPORT_CA_DIR +#endif +#if GNUTLS_VERSION_NUMBER >= 0x030014 +# define SUPPORT_SYSDEFAULT_CABUNDLE +#endif +#if GNUTLS_VERSION_NUMBER >= 0x030109 +# define SUPPORT_CORK +#endif + +#ifndef DISABLE_OCSP +# include +#endif /* GnuTLS 2 vs 3 @@ -53,7 +81,8 @@ Changes: /* Values for verify_requirement */ -enum peer_verify_requirement { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; +enum peer_verify_requirement + { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; /* This holds most state for server or client; with this, we can set up an outbound TLS-enabled connection in an ACL callout, while not stomping all @@ -63,22 +92,24 @@ Some of these correspond to variables in globals.c; those variables will be set to point to content in one of these instances, as appropriate for the stage of the process lifetime. -Not handled here: globals tls_active, tls_bits, tls_cipher, tls_peerdn, -tls_certificate_verified, tls_channelbinding_b64, tls_sni. +Not handled here: global tls_channelbinding_b64. */ typedef struct exim_gnutls_state { - gnutls_session_t session; + gnutls_session_t session; gnutls_certificate_credentials_t x509_cred; - gnutls_priority_t priority_cache; + gnutls_priority_t priority_cache; enum peer_verify_requirement verify_requirement; - int fd_in; - int fd_out; - BOOL peer_cert_verified; - BOOL trigger_sni_changes; + int fd_in; + int fd_out; + BOOL peer_cert_verified; + BOOL trigger_sni_changes; + BOOL have_set_peerdn; const struct host_item *host; - uschar *peerdn; - uschar *received_sni; + gnutls_x509_crt_t peercert; + uschar *peerdn; + uschar *ciphersuite; + uschar *received_sni; const uschar *tls_certificate; const uschar *tls_privatekey; @@ -86,29 +117,67 @@ typedef struct exim_gnutls_state { const uschar *tls_verify_certificates; const uschar *tls_crl; const uschar *tls_require_ciphers; + uschar *exp_tls_certificate; uschar *exp_tls_privatekey; - uschar *exp_tls_sni; uschar *exp_tls_verify_certificates; uschar *exp_tls_crl; uschar *exp_tls_require_ciphers; + uschar *exp_tls_ocsp_file; + const uschar *exp_tls_verify_cert_hostnames; +#ifndef DISABLE_EVENT + uschar *event_action; +#endif + + tls_support *tlsp; /* set in tls_init() */ uschar *xfer_buffer; int xfer_buffer_lwm; int xfer_buffer_hwm; int xfer_eof; int xfer_error; - - uschar cipherbuf[256]; } exim_gnutls_state_st; static const exim_gnutls_state_st exim_gnutls_state_init = { - NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, - NULL, NULL, NULL, - NULL, NULL, NULL, NULL, NULL, NULL, - NULL, NULL, NULL, NULL, NULL, NULL, - NULL, 0, 0, 0, 0, - "" + .session = NULL, + .x509_cred = NULL, + .priority_cache = NULL, + .verify_requirement = VERIFY_NONE, + .fd_in = -1, + .fd_out = -1, + .peer_cert_verified = FALSE, + .trigger_sni_changes =FALSE, + .have_set_peerdn = FALSE, + .host = NULL, + .peercert = NULL, + .peerdn = NULL, + .ciphersuite = NULL, + .received_sni = NULL, + + .tls_certificate = NULL, + .tls_privatekey = NULL, + .tls_sni = NULL, + .tls_verify_certificates = NULL, + .tls_crl = NULL, + .tls_require_ciphers =NULL, + + .exp_tls_certificate = NULL, + .exp_tls_privatekey = NULL, + .exp_tls_verify_certificates = NULL, + .exp_tls_crl = NULL, + .exp_tls_require_ciphers = NULL, + .exp_tls_ocsp_file = NULL, + .exp_tls_verify_cert_hostnames = NULL, +#ifndef DISABLE_EVENT + .event_action = NULL, +#endif + .tlsp = NULL, + + .xfer_buffer = NULL, + .xfer_buffer_lwm = 0, + .xfer_buffer_hwm = 0, + .xfer_eof = 0, + .xfer_error = 0, }; /* Not only do we have our own APIs which don't pass around state, assuming @@ -118,10 +187,11 @@ context we're currently dealing with" pointer and rely upon being single-threaded to keep from processing data on an inbound TLS connection while talking to another TLS connection for an outbound check. This does mean that there's no way for heart-beats to be responded to, for the duration of the -second connection. */ +second connection. +XXX But see gnutls_session_get_ptr() +*/ static exim_gnutls_state_st state_server, state_client; -static exim_gnutls_state_st *current_global_tls_state; /* dh_params are initialised once within the lifetime of a process using TLS; if we used TLS in a long-lived daemon, we'd have to reconsider this. But we @@ -139,6 +209,10 @@ static const char * const exim_default_gnutls_priority = "NORMAL"; static BOOL exim_gnutls_base_init_done = FALSE; +#ifndef DISABLE_OCSP +static BOOL gnutls_buggy_ocsp = FALSE; +#endif + /* ------------------------------------------------------------------------ */ /* macros */ @@ -148,24 +222,42 @@ static BOOL exim_gnutls_base_init_done = FALSE; /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup the library logging; a value less than 0 disables the calls to set up logging callbacks. */ -#define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 +#ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL +# define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 +#endif -#define EXIM_CLIENT_DH_MIN_BITS 1024 +#ifndef EXIM_CLIENT_DH_MIN_BITS +# define EXIM_CLIENT_DH_MIN_BITS 1024 +#endif /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we can ask for a bit-strength. Without that, we stick to the constant we had before, for now. */ -#define EXIM_SERVER_DH_BITS_PRE2_12 1024 +#ifndef EXIM_SERVER_DH_BITS_PRE2_12 +# define EXIM_SERVER_DH_BITS_PRE2_12 1024 +#endif #define exim_gnutls_err_check(Label) do { \ - if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) + if (rc != GNUTLS_E_SUCCESS) \ + return tls_error((Label), gnutls_strerror(rc), host, errstr); \ + } while (0) -#define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) +#define expand_check_tlsvar(Varname, errstr) \ + expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) #if GNUTLS_VERSION_NUMBER >= 0x020c00 -#define HAVE_GNUTLS_SESSION_CHANNEL_BINDING -#define HAVE_GNUTLS_SEC_PARAM_CONSTANTS -#define HAVE_GNUTLS_RND +# define HAVE_GNUTLS_SESSION_CHANNEL_BINDING +# define HAVE_GNUTLS_SEC_PARAM_CONSTANTS +# define HAVE_GNUTLS_RND +/* The security fix we provide with the gnutls_allow_auto_pkcs11 option + * (4.82 PP/09) introduces a compatibility regression. The symbol simply + * isn't available sometimes, so this needs to become a conditional + * compilation; the sanest way to deal with this being a problem on + * older OSes is to block it in the Local/Makefile with this compiler + * definition */ +# ifndef AVOID_GNUTLS_PKCS11 +# define HAVE_GNUTLS_PKCS11 +# endif /* AVOID_GNUTLS_PKCS11 */ #endif @@ -180,6 +272,10 @@ static void exim_gnutls_logger_cb(int level, const char *message); static int exim_sni_handling_cb(gnutls_session_t session); +#ifndef DISABLE_OCSP +static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, + gnutls_datum_t * ocsp_response); +#endif @@ -203,28 +299,18 @@ Argument: usually obtained from gnutls_strerror() host NULL if setting up a server; the connected host if setting up a client + errstr pointer to returned error string Returns: OK/DEFER/FAIL */ static int -tls_error(const uschar *prefix, const char *msg, const host_item *host) +tls_error(const uschar *prefix, const char *msg, const host_item *host, + uschar ** errstr) { -if (host) - { - log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", - host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); - return FAIL; - } -else - { - uschar *conn_info = smtp_get_connection_info(); - if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) - conn_info += 5; - log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", - conn_info, prefix, msg ? ": " : "", msg ? msg : ""); - return DEFER; - } +if (errstr) + *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : ""); +return host ? FAIL : DEFER; } @@ -248,7 +334,8 @@ Returns: nothing static void record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) { -const char *msg; +const char * msg; +uschar * errstr; if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), @@ -256,7 +343,18 @@ if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) else msg = gnutls_strerror(rc); -tls_error(when, msg, state->host); +(void) tls_error(when, msg, state->host, &errstr); + +if (state->host) + log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", + state->host->name, state->host->address, errstr); +else + { + uschar * conn_info = smtp_get_connection_info(); + if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; + /* I'd like to get separated H= here, but too hard for now */ + log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); + } } @@ -266,12 +364,40 @@ tls_error(when, msg, state->host); * Set various Exim expansion vars * *************************************************/ +#define exim_gnutls_cert_err(Label) \ + do \ + { \ + if (rc != GNUTLS_E_SUCCESS) \ + { \ + DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ + (Label), gnutls_strerror(rc)); \ + return rc; \ + } \ + } while (0) + +static int +import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) +{ +int rc; + +rc = gnutls_x509_crt_init(crtp); +exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); + +rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); +exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); + +return rc; +} + +#undef exim_gnutls_cert_err + + /* We set various Exim global variables from the state, once a session has been established. With TLS callouts, may need to change this to stack variables, or just re-call it with the server state after client callout has finished. -Make sure anything set here is inset in tls_getc(). +Make sure anything set here is unset in tls_getc(). Sets: tls_active fd @@ -279,61 +405,37 @@ Sets: tls_certificate_verified bool indicator tls_channelbinding_b64 for some SASL mechanisms tls_cipher a string + tls_peercert pointer to library internal tls_peerdn a string tls_sni a (UTF-8) string -Also: - current_global_tls_state for API limitations + tls_ourcert pointer to library internal Argument: state the relevant exim_gnutls_state_st * */ static void -extract_exim_vars_from_tls_state(exim_gnutls_state_st *state) +extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) { -gnutls_protocol_t protocol; gnutls_cipher_algorithm_t cipher; -gnutls_kx_algorithm_t kx; -gnutls_mac_algorithm_t mac; -uschar *p; #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING int old_pool; int rc; gnutls_datum_t channel; #endif +tls_support * tlsp = state->tlsp; -current_global_tls_state = state; - -tls_active = state->fd_out; +tlsp->active = state->fd_out; cipher = gnutls_cipher_get(state->session); /* returns size in "bytes" */ -tls_bits = gnutls_cipher_get_key_size(cipher) * 8; +tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; -if (!*state->cipherbuf) - { - protocol = gnutls_protocol_get_version(state->session); - mac = gnutls_mac_get(state->session); - kx = gnutls_kx_get(state->session); +tlsp->cipher = state->ciphersuite; - string_format(state->cipherbuf, sizeof(state->cipherbuf), - "%s:%s:%u", - gnutls_protocol_get_name(protocol), - gnutls_cipher_suite_get_name(kx, cipher, mac), - tls_bits); +DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); - /* I don't see a way that spaces could occur, in the current GnuTLS - code base, but it was a concern in the old code and perhaps older GnuTLS - releases did return "TLS 1.0"; play it safe, just in case. */ - for (p = state->cipherbuf; *p != '\0'; ++p) - if (isspace(*p)) - *p = '-'; - } -tls_cipher = state->cipherbuf; - -DEBUG(D_tls) debug_printf("cipher: %s\n", tls_cipher); - -tls_certificate_verified = state->peer_cert_verified; +tlsp->certificate_verified = state->peer_cert_verified; /* note that tls_channelbinding_b64 is not saved to the spool file, since it's only available for use for authenticators while this TLS session is running. */ @@ -348,15 +450,23 @@ if (rc) { } else { old_pool = store_pool; store_pool = POOL_PERM; - tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); + tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); store_pool = old_pool; DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); } #endif -tls_peerdn = state->peerdn; +/* peercert is set in peer_status() */ +tlsp->peerdn = state->peerdn; +tlsp->sni = state->received_sni; + +/* record our certificate */ + { + const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); + gnutls_x509_crt_t crt; -tls_sni = state->received_sni; + tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; + } } @@ -376,20 +486,21 @@ file is never present. If two processes both compute some new parameters, you waste a bit of effort, but it doesn't seem worth messing around with locking to prevent this. -Argument: - host NULL for server, server for client (for error handling) - Returns: OK/DEFER/FAIL */ static int -init_server_dh(void) +init_server_dh(uschar ** errstr) { int fd, rc; unsigned int dh_bits; -gnutls_datum m; -uschar filename[PATH_MAX]; +gnutls_datum_t m; +uschar filename_buf[PATH_MAX]; +uschar *filename = NULL; size_t sz; +uschar *exp_tls_dhparam; +BOOL use_file_in_spool = FALSE; +BOOL use_fixed_file = FALSE; host_item *host = NULL; /* dummy for macros */ DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); @@ -397,12 +508,51 @@ DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); rc = gnutls_dh_params_init(&dh_server_params); exim_gnutls_err_check(US"gnutls_dh_params_init"); +m.data = NULL; +m.size = 0; + +if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) + return DEFER; + +if (!exp_tls_dhparam) + { + DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); + m.data = US std_dh_prime_default(); + m.size = Ustrlen(m.data); + } +else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) + use_file_in_spool = TRUE; +else if (Ustrcmp(exp_tls_dhparam, "none") == 0) + { + DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); + return OK; + } +else if (exp_tls_dhparam[0] != '/') + { + if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) + return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL, errstr); + m.size = Ustrlen(m.data); + } +else + { + use_fixed_file = TRUE; + filename = exp_tls_dhparam; + } + +if (m.data) + { + rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); + exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); + DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); + return OK; + } + #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS /* If you change this constant, also change dh_param_fn_ext so that we can use a different filename and ensure we have sufficient bits. */ dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); if (!dh_bits) - return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); + return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); DEBUG(D_tls) debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", dh_bits); @@ -413,15 +563,27 @@ DEBUG(D_tls) dh_bits); #endif -if (!string_format(filename, sizeof(filename), - "%s/gnutls-params-%d", spool_directory, dh_bits)) - return tls_error(US"overlong filename", NULL, NULL); +/* Some clients have hard-coded limits. */ +if (dh_bits > tls_dh_max_bits) + { + DEBUG(D_tls) + debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", + tls_dh_max_bits); + dh_bits = tls_dh_max_bits; + } + +if (use_file_in_spool) + { + if (!string_format(filename_buf, sizeof(filename_buf), + "%s/gnutls-params-%d", spool_directory, dh_bits)) + return tls_error(US"overlong filename", NULL, NULL, errstr); + filename = filename_buf; + } /* Open the cache file for reading and if successful, read it and set up the parameters. */ -fd = Uopen(filename, O_RDONLY, 0); -if (fd >= 0) +if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) { struct stat statbuf; FILE *fp; @@ -431,36 +593,33 @@ if (fd >= 0) { saved_errno = errno; (void)close(fd); - return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); + return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL, errstr); } if (!S_ISREG(statbuf.st_mode)) { (void)close(fd); - return tls_error(US"TLS cache not a file", NULL, NULL); + return tls_error(US"TLS cache not a file", NULL, NULL, errstr); } - fp = fdopen(fd, "rb"); - if (!fp) + if (!(fp = fdopen(fd, "rb"))) { saved_errno = errno; (void)close(fd); return tls_error(US"fdopen(TLS cache stat fd) failed", - strerror(saved_errno), NULL); + strerror(saved_errno), NULL, errstr); } m.size = statbuf.st_size; - m.data = malloc(m.size); - if (m.data == NULL) + if (!(m.data = malloc(m.size))) { fclose(fp); - return tls_error(US"malloc failed", strerror(errno), NULL); + return tls_error(US"malloc failed", strerror(errno), NULL, errstr); } - sz = fread(m.data, m.size, 1, fp); - if (!sz) + if (!(sz = fread(m.data, m.size, 1, fp))) { saved_errno = errno; fclose(fp); free(m.data); - return tls_error(US"fread failed", strerror(saved_errno), NULL); + return tls_error(US"fread failed", strerror(saved_errno), NULL, errstr); } fclose(fp); @@ -481,7 +640,7 @@ else if (errno == ENOENT) } else return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), - NULL, NULL); + NULL, NULL, errstr); /* If ret < 0, either the cache file does not exist, or the data it contains is not useful. One particular case of this is when upgrading from an older @@ -492,19 +651,37 @@ case. */ if (rc < 0) { uschar *temp_fn; + unsigned int dh_bits_gen = dh_bits; if ((PATH_MAX - Ustrlen(filename)) < 10) return tls_error(US"Filename too long to generate replacement", - CS filename, NULL); + CS filename, NULL, errstr); temp_fn = string_copy(US "%s.XXXXXXX"); - fd = mkstemp(CS temp_fn); /* modifies temp_fn */ - if (fd < 0) - return tls_error(US"Unable to open temp file", strerror(errno), NULL); + if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ + return tls_error(US"Unable to open temp file", strerror(errno), NULL, errstr); (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ - DEBUG(D_tls) debug_printf("generating %d bits Diffie-Hellman key ...\n", dh_bits); - rc = gnutls_dh_params_generate2(dh_server_params, dh_bits); + /* GnuTLS overshoots! + * If we ask for 2236, we might get 2237 or more. + * But there's no way to ask GnuTLS how many bits there really are. + * We can ask how many bits were used in a TLS session, but that's it! + * The prime itself is hidden behind too much abstraction. + * So we ask for less, and proceed on a wing and a prayer. + * First attempt, subtracted 3 for 2233 and got 2240. + */ + if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) + { + dh_bits_gen = dh_bits - 10; + DEBUG(D_tls) + debug_printf("being paranoid about DH generation, make it '%d' bits'\n", + dh_bits_gen); + } + + DEBUG(D_tls) + debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", + dh_bits_gen); + rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); exim_gnutls_err_check(US"gnutls_dh_params_generate2"); /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, @@ -518,9 +695,10 @@ if (rc < 0) if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); m.size = sz; - m.data = malloc(m.size); - if (m.data == NULL) - return tls_error(US"memory allocation failed", strerror(errno), NULL); + if (!(m.data = malloc(m.size))) + return tls_error(US"memory allocation failed", strerror(errno), NULL, errstr); + + /* this will return a size 1 less than the allocation size above */ rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, m.data, &sz); if (rc != GNUTLS_E_SUCCESS) @@ -528,28 +706,25 @@ if (rc < 0) free(m.data); exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); } + m.size = sz; /* shrink by 1, probably */ - sz = write_to_fd_buf(fd, m.data, (size_t) m.size); - if (sz != m.size) + if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) { free(m.data); return tls_error(US"TLS cache write D-H params failed", - strerror(errno), NULL); + strerror(errno), NULL, errstr); } free(m.data); - sz = write_to_fd_buf(fd, US"\n", 1); - if (sz != 1) + if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) return tls_error(US"TLS cache write D-H params final newline failed", - strerror(errno), NULL); + strerror(errno), NULL, errstr); - rc = close(fd); - if (rc) - return tls_error(US"TLS cache write close() failed", - strerror(errno), NULL); + if ((rc = close(fd))) + return tls_error(US"TLS cache write close() failed", strerror(errno), NULL, errstr); if (Urename(temp_fn, filename) < 0) return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", - temp_fn, filename), strerror(errno), NULL); + temp_fn, filename), strerror(errno), NULL, errstr); DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); } @@ -561,6 +736,74 @@ return OK; +/* Create and install a selfsigned certificate, for use in server mode */ + +static int +tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) +{ +gnutls_x509_crt_t cert = NULL; +time_t now; +gnutls_x509_privkey_t pkey = NULL; +const uschar * where; +int rc; + +where = US"initialising pkey"; +if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; + +where = US"initialising cert"; +if ((rc = gnutls_x509_crt_init(&cert))) goto err; + +where = US"generating pkey"; +if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, +#ifdef SUPPORT_PARAM_TO_PK_BITS + gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), +#else + 1024, +#endif + 0))) + goto err; + +where = US"configuring cert"; +now = 0; +if ( (rc = gnutls_x509_crt_set_version(cert, 3)) + || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) + || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) + || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ + || (rc = gnutls_x509_crt_set_key(cert, pkey)) + + || (rc = gnutls_x509_crt_set_dn_by_oid(cert, + GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) + || (rc = gnutls_x509_crt_set_dn_by_oid(cert, + GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) + || (rc = gnutls_x509_crt_set_dn_by_oid(cert, + GNUTLS_OID_X520_COMMON_NAME, 0, + smtp_active_hostname, Ustrlen(smtp_active_hostname))) + ) + goto err; + +where = US"signing cert"; +if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; + +where = US"installing selfsign cert"; + /* Since: 2.4.0 */ +if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) + goto err; + +rc = OK; + +out: + if (cert) gnutls_x509_crt_deinit(cert); + if (pkey) gnutls_x509_privkey_deinit(pkey); + return rc; + +err: + rc = tls_error(where, gnutls_strerror(rc), NULL, errstr); + goto out; +} + + + + /************************************************* * Variables re-expanded post-SNI * *************************************************/ @@ -575,13 +818,15 @@ which we are responsible for setting on the first pass through. Arguments: state exim_gnutls_state_st * + errstr error string pointer Returns: OK/DEFER/FAIL */ static int -tls_expand_session_files(exim_gnutls_state_st *state) +tls_expand_session_files(exim_gnutls_state_st *state, uschar ** errstr) { +struct stat statbuf; int rc; const host_item *host = state->host; /* macro should be reconsidered? */ uschar *saved_tls_certificate = NULL; @@ -591,11 +836,14 @@ uschar *saved_tls_crl = NULL; int cert_count; /* We check for tls_sni *before* expansion. */ -if (!state->host) - { +if (!host) /* server */ if (!state->received_sni) { - if (Ustrstr(state->tls_certificate, US"tls_sni")) + if (state->tls_certificate && + (Ustrstr(state->tls_certificate, US"tls_sni") || + Ustrstr(state->tls_certificate, US"tls_in_sni") || + Ustrstr(state->tls_certificate, US"tls_out_sni") + )) { DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); state->trigger_sni_changes = TRUE; @@ -603,12 +851,15 @@ if (!state->host) } else { + /* useful for debugging */ saved_tls_certificate = state->exp_tls_certificate; saved_tls_privatekey = state->exp_tls_privatekey; saved_tls_verify_certificates = state->exp_tls_verify_certificates; saved_tls_crl = state->exp_tls_crl; } - } + +rc = gnutls_certificate_allocate_credentials(&state->x509_cred); +exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); /* remember: expand_check_tlsvar() is expand_check() but fiddling with state members, assuming consistent naming; and expand_check() returns @@ -617,21 +868,20 @@ false if expansion failed, unless expansion was forced to fail. */ /* check if we at least have a certificate, before doing expensive D-H generation. */ -if (!expand_check_tlsvar(tls_certificate)) +if (!expand_check_tlsvar(tls_certificate, errstr)) return DEFER; /* certificate is mandatory in server, optional in client */ -if ((state->exp_tls_certificate == NULL) || - (*state->exp_tls_certificate == '\0')) - { - if (state->host == NULL) - return tls_error(US"no TLS server certificate is specified", NULL, NULL); +if ( !state->exp_tls_certificate + || !*state->exp_tls_certificate + ) + if (!host) + return tls_install_selfsign(state, errstr); else DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); - } -if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) +if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) return DEFER; /* tls_privatekey is optional, defaulting to same file as certificate */ @@ -645,35 +895,60 @@ if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') if (state->exp_tls_certificate && *state->exp_tls_certificate) { - BOOL setit = TRUE; DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", state->exp_tls_certificate, state->exp_tls_privatekey); if (state->received_sni) - { - if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && - (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) + if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 + && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 + ) { DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); - setit = FALSE; } else { DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); } - } - if (setit) + rc = gnutls_certificate_set_x509_key_file(state->x509_cred, + CS state->exp_tls_certificate, CS state->exp_tls_privatekey, + GNUTLS_X509_FMT_PEM); + exim_gnutls_err_check( + string_sprintf("cert/key setup: cert=%s key=%s", + state->exp_tls_certificate, state->exp_tls_privatekey)); + DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); + } /* tls_certificate */ + + +/* Set the OCSP stapling server info */ + +#ifndef DISABLE_OCSP +if ( !host /* server */ + && tls_ocsp_file + ) + { + if (gnutls_buggy_ocsp) { - rc = gnutls_certificate_set_x509_key_file(state->x509_cred, - CS state->exp_tls_certificate, CS state->exp_tls_privatekey, - GNUTLS_X509_FMT_PEM); - exim_gnutls_err_check( - string_sprintf("cert/key setup: cert=%s key=%s", - state->exp_tls_certificate, state->exp_tls_privatekey)); - DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); + DEBUG(D_tls) debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); } - } /* tls_certificate */ + else + { + if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", + &state->exp_tls_ocsp_file, errstr)) + return DEFER; + + /* Use the full callback method for stapling just to get observability. + More efficient would be to read the file once only, if it never changed + (due to SNI). Would need restart on file update, or watch datestamp. */ + + gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, + server_ocsp_stapling_cb, state->exp_tls_ocsp_file); + + DEBUG(D_tls) debug_printf("OCSP response file = %s\n", state->exp_tls_ocsp_file); + } + } +#endif + /* Set the trusted CAs file if one is provided, and then add the CRL if one is provided. Experiment shows that, if the certificate file is empty, an unhelpful @@ -683,116 +958,195 @@ behaviour. */ if (state->tls_verify_certificates && *state->tls_verify_certificates) { - struct stat statbuf; - BOOL setit_vc = TRUE, setit_crl = TRUE; - - if (!expand_check_tlsvar(tls_verify_certificates)) + if (!expand_check_tlsvar(tls_verify_certificates, errstr)) return DEFER; +#ifndef SUPPORT_SYSDEFAULT_CABUNDLE + if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) + state->exp_tls_verify_certificates = NULL; +#endif if (state->tls_crl && *state->tls_crl) - if (!expand_check_tlsvar(tls_crl)) + if (!expand_check_tlsvar(tls_crl, errstr)) return DEFER; - if (state->received_sni) - { - state->exp_tls_verify_certificates, state->exp_tls_verify_certificates, - saved_tls_verify_certificates, saved_tls_verify_certificates); - if (!(state->exp_tls_verify_certificates || saved_tls_verify_certificates)) - setit_vc = FALSE; /* never was set */ - else if (!state->exp_tls_verify_certificates || !saved_tls_verify_certificates) - setit_vc = TRUE; /* changed whether set */ - else if (Ustrcmp(state->exp_tls_verify_certificates, saved_tls_verify_certificates) == 0) - setit_vc = FALSE; /* not changed value */ - - state->exp_tls_crl, state->exp_tls_crl, - saved_tls_crl, saved_tls_crl); - if (!(state->exp_tls_crl || saved_tls_crl)) - setit_crl = FALSE; /* never was set */ - else if (!state->exp_tls_crl || !saved_tls_crl) - setit_crl = TRUE; /* changed whether set */ - else if (Ustrcmp(state->exp_tls_crl, saved_tls_crl) == 0) - setit_crl = FALSE; /* not changed value */ - } - - /* nb: early exit; change if add more expansions to this function */ - if (!(setit_vc || setit_crl)) + if (!(state->exp_tls_verify_certificates && + *state->exp_tls_verify_certificates)) { DEBUG(D_tls) - debug_printf("TLS SNI: no change to tls_crl or tls_verify_certificates\n"); + debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); + /* With no tls_verify_certificates, we ignore tls_crl too */ return OK; } + } +else + { + DEBUG(D_tls) + debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); + return OK; + } +#ifdef SUPPORT_SYSDEFAULT_CABUNDLE +if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) + cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); +else +#endif + { if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) { log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " - "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, - strerror(errno)); + "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, + strerror(errno)); return DEFER; } - if (!S_ISREG(statbuf.st_mode)) +#ifndef SUPPORT_CA_DIR + /* The test suite passes in /dev/null; we could check for that path explicitly, + but who knows if someone has some weird FIFO which always dumps some certs, or + other weirdness. The thing we really want to check is that it's not a + directory, since while OpenSSL supports that, GnuTLS does not. + So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ + if (S_ISDIR(statbuf.st_mode)) { DEBUG(D_tls) - debug_printf("verify certificates path is not a file: \"%s\"\n%s\n", - state->exp_tls_verify_certificates, - S_ISDIR(statbuf.st_mode) - ? " it's a directory, that's OpenSSL, this is GnuTLS" - : " (not a directory either)"); + debug_printf("verify certificates path is a dir: \"%s\"\n", + state->exp_tls_verify_certificates); log_write(0, LOG_MAIN|LOG_PANIC, - "tls_verify_certificates \"%s\" is not a file", - state->exp_tls_verify_certificates); + "tls_verify_certificates \"%s\" is a directory", + state->exp_tls_verify_certificates); return DEFER; } +#endif DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", - state->exp_tls_verify_certificates, statbuf.st_size); - - /* If the CA cert file is empty, there's no point in loading the CRL file, - as we aren't verifying, so checking for revocation is pointless. */ + state->exp_tls_verify_certificates, statbuf.st_size); - if (statbuf.st_size > 0) + if (statbuf.st_size == 0) { - if (setit_vc) - { - cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, - CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); - if (cert_count < 0) - { - rc = cert_count; - exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); - } - DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); - } - else - { - DEBUG(D_tls) debug_printf("TLS SNI: tls_verify_certificates unchanged\n"); - } - - if (setit_crl && state->tls_crl && *state->tls_crl) - { - if (state->exp_tls_crl && *state->exp_tls_crl) - { - DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); - rc = gnutls_certificate_set_x509_crl_file(state->x509_cred, - CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); - exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); - } - } DEBUG(D_tls) - if (!setit_crl) debug_printf("TLS SNI: tls_crl unchanged\n"); - } /* statbuf.st_size */ - } /* tls_verify_certificates */ + debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); + return OK; + } + + cert_count = + +#ifdef SUPPORT_CA_DIR + (statbuf.st_mode & S_IFMT) == S_IFDIR + ? + gnutls_certificate_set_x509_trust_dir(state->x509_cred, + CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) + : +#endif + gnutls_certificate_set_x509_trust_file(state->x509_cred, + CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); + } + +if (cert_count < 0) + { + rc = cert_count; + exim_gnutls_err_check(US"setting certificate trust"); + } +DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); + +if (state->tls_crl && *state->tls_crl && + state->exp_tls_crl && *state->exp_tls_crl) + { + DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); + cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, + CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); + if (cert_count < 0) + { + rc = cert_count; + exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); + } + DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); + } return OK; -/* also above, during verify_certificates/crl, during SNI, if unchanged */ } +/************************************************* +* Set X.509 state variables * +*************************************************/ + +/* In GnuTLS, the registered cert/key are not replaced by a later +set of a cert/key, so for SNI support we need a whole new x509_cred +structure. Which means various other non-re-expanded pieces of state +need to be re-set in the new struct, so the setting logic is pulled +out to this. + +Arguments: + state exim_gnutls_state_st * + errstr error string pointer + +Returns: OK/DEFER/FAIL +*/ + +static int +tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) +{ +int rc; +const host_item *host = state->host; /* macro should be reconsidered? */ + +/* Create D-H parameters, or read them from the cache file. This function does +its own SMTP error messaging. This only happens for the server, TLS D-H ignores +client-side params. */ + +if (!state->host) + { + if (!dh_server_params) + { + rc = init_server_dh(errstr); + if (rc != OK) return rc; + } + gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); + } + +/* Link the credentials to the session. */ + +rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); +exim_gnutls_err_check(US"gnutls_credentials_set"); + +return OK; +} + /************************************************* * Initialize for GnuTLS * *************************************************/ + +#ifndef DISABLE_OCSP + +static BOOL +tls_is_buggy_ocsp(void) +{ +const uschar * s; +uschar maj, mid, mic; + +s = CUS gnutls_check_version(NULL); +maj = atoi(CCS s); +if (maj == 3) + { + while (*s && *s != '.') s++; + mid = atoi(CCS ++s); + if (mid <= 2) + return TRUE; + else if (mid >= 5) + return FALSE; + else + { + while (*s && *s != '.') s++; + mic = atoi(CCS ++s); + return mic <= (mid == 3 ? 16 : 3); + } + } +return FALSE; +} + +#endif + + /* Called from both server and client code. In the case of a server, errors before actual TLS negotiation return DEFER. @@ -804,6 +1158,8 @@ Arguments: cas CA certs file crl CRL file require_ciphers tls_require_ciphers setting + caller_state returned state-info structure + errstr error string pointer Returns: OK/DEFER/FAIL */ @@ -817,7 +1173,8 @@ tls_init( const uschar *cas, const uschar *crl, const uschar *require_ciphers, - exim_gnutls_state_st **caller_state) + exim_gnutls_state_st **caller_state, + uschar ** errstr) { exim_gnutls_state_st *state; int rc; @@ -830,6 +1187,19 @@ if (!exim_gnutls_base_init_done) { DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); +#ifdef HAVE_GNUTLS_PKCS11 + /* By default, gnutls_global_init will init PKCS11 support in auto mode, + which loads modules from a config file, which sounds good and may be wanted + by some sysadmin, but also means in common configurations that GNOME keyring + environment variables are used and so breaks for users calling mailq. + To prevent this, we init PKCS11 first, which is the documented approach. */ + if (!gnutls_allow_auto_pkcs11) + { + rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); + exim_gnutls_err_check(US"gnutls_pkcs11_init"); + } +#endif + rc = gnutls_global_init(); exim_gnutls_err_check(US"gnutls_global_init"); @@ -842,6 +1212,11 @@ if (!exim_gnutls_base_init_done) } #endif +#ifndef DISABLE_OCSP + if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) + log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); +#endif + exim_gnutls_base_init_done = TRUE; } @@ -849,6 +1224,7 @@ if (host) { state = &state_client; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); + state->tlsp = &tls_out; DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); rc = gnutls_init(&state->session, GNUTLS_CLIENT); } @@ -856,6 +1232,7 @@ else { state = &state_server; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); + state->tlsp = &tls_in; DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); rc = gnutls_init(&state->session, GNUTLS_SERVER); } @@ -865,49 +1242,35 @@ state->host = host; state->tls_certificate = certificate; state->tls_privatekey = privatekey; +state->tls_require_ciphers = require_ciphers; state->tls_sni = sni; state->tls_verify_certificates = cas; state->tls_crl = crl; -rc = gnutls_certificate_allocate_credentials(&state->x509_cred); -exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); - /* This handles the variables that might get re-expanded after TLS SNI; that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ DEBUG(D_tls) debug_printf("Expanding various TLS configuration options for session credentials.\n"); -rc = tls_expand_session_files(state); -if (rc != OK) return rc; +if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; -/* Create D-H parameters, or read them from the cache file. This function does -its own SMTP error messaging. This only happens for the server, TLS D-H ignores -client-side params. */ +/* These are all other parts of the x509_cred handling, since SNI in GnuTLS +requires a new structure afterwards. */ -if (!host) - { - rc = init_server_dh(); - if (rc != OK) return rc; - gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); - } - -/* Link the credentials to the session. */ - -rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); -exim_gnutls_err_check(US"gnutls_credentials_set"); +if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; /* set SNI in client, only */ if (host) { - if (!expand_check_tlsvar(tls_sni)) + if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) return DEFER; - if (state->exp_tls_sni && *state->exp_tls_sni) + if (state->tlsp->sni && *state->tlsp->sni) { DEBUG(D_tls) - debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni); - sz = Ustrlen(state->exp_tls_sni); + debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); + sz = Ustrlen(state->tlsp->sni); rc = gnutls_server_name_set(state->session, - GNUTLS_NAME_DNS, state->exp_tls_sni, sz); + GNUTLS_NAME_DNS, state->tlsp->sni, sz); exim_gnutls_err_check(US"gnutls_server_name_set"); } } @@ -916,7 +1279,7 @@ else if (state->tls_sni) "have an SNI set for a client [%s]\n", state->tls_sni); /* This is the priority string support, -http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html +http://www.gnutls.org/manual/html_node/Priority-Strings.html and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. This was backwards incompatible, but means Exim no longer needs to track all algorithms and provide string forms for them. */ @@ -925,7 +1288,7 @@ want_default_priorities = TRUE; if (state->tls_require_ciphers && *state->tls_require_ciphers) { - if (!expand_check_tlsvar(tls_require_ciphers)) + if (!expand_check_tlsvar(tls_require_ciphers, errstr)) return DEFER; if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) { @@ -940,6 +1303,9 @@ if (state->tls_require_ciphers && *state->tls_require_ciphers) } if (want_default_priorities) { + DEBUG(D_tls) + debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", + exim_default_gnutls_priority); rc = gnutls_priority_init(&state->priority_cache, exim_default_gnutls_priority, &errpos); p = US exim_default_gnutls_priority; @@ -967,53 +1333,96 @@ if (gnutls_compat_mode) } *caller_state = state; -/* needs to happen before callbacks during handshake */ -current_global_tls_state = state; return OK; } - /************************************************* * Extract peer information * *************************************************/ /* Called from both server and client code. -Only this is allowed to set state->peerdn and we use that to detect double-calls. +Only this is allowed to set state->peerdn and state->have_set_peerdn +and we use that to detect double-calls. + +NOTE: the state blocks last while the TLS connection is up, which is fine +for logging in the server side, but for the client side, we log after teardown +in src/deliver.c. While the session is up, we can twist about states and +repoint tls_* globals, but those variables used for logging or other variable +expansion that happens _after_ delivery need to have a longer life-time. + +So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from +doing this more than once per generation of a state context. We set them in +the state context, and repoint tls_* to them. After the state goes away, the +tls_* copies of the pointers remain valid and client delivery logging is happy. + +tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues +don't apply. Arguments: state exim_gnutls_state_st * + errstr pointer to error string Returns: OK/DEFER/FAIL */ static int -peer_status(exim_gnutls_state_st *state) +peer_status(exim_gnutls_state_st *state, uschar ** errstr) { -const gnutls_datum *cert_list; -int rc; +uschar cipherbuf[256]; +const gnutls_datum_t *cert_list; +int old_pool, rc; unsigned int cert_list_size = 0; +gnutls_protocol_t protocol; +gnutls_cipher_algorithm_t cipher; +gnutls_kx_algorithm_t kx; +gnutls_mac_algorithm_t mac; gnutls_certificate_type_t ct; gnutls_x509_crt_t crt; -uschar *dn_buf; +uschar *p, *dn_buf; size_t sz; -if (state->peerdn) +if (state->have_set_peerdn) return OK; +state->have_set_peerdn = TRUE; -state->peerdn = US"unknown"; +state->peerdn = NULL; +/* tls_cipher */ +cipher = gnutls_cipher_get(state->session); +protocol = gnutls_protocol_get_version(state->session); +mac = gnutls_mac_get(state->session); +kx = gnutls_kx_get(state->session); + +string_format(cipherbuf, sizeof(cipherbuf), + "%s:%s:%d", + gnutls_protocol_get_name(protocol), + gnutls_cipher_suite_get_name(kx, cipher, mac), + (int) gnutls_cipher_get_key_size(cipher) * 8); + +/* I don't see a way that spaces could occur, in the current GnuTLS +code base, but it was a concern in the old code and perhaps older GnuTLS +releases did return "TLS 1.0"; play it safe, just in case. */ +for (p = cipherbuf; *p != '\0'; ++p) + if (isspace(*p)) + *p = '-'; +old_pool = store_pool; +store_pool = POOL_PERM; +state->ciphersuite = string_copy(cipherbuf); +store_pool = old_pool; +state->tlsp->cipher = state->ciphersuite; + +/* tls_peerdn */ cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); if (cert_list == NULL || cert_list_size == 0) { - state->peerdn = US"unknown (no certificate)"; DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", cert_list, cert_list_size); - if (state->verify_requirement == VERIFY_REQUIRED) + if (state->verify_requirement >= VERIFY_REQUIRED) return tls_error(US"certificate verification failed", - "no certificate received from peer", state->host); + "no certificate received from peer", state->host, errstr); return OK; } @@ -1021,26 +1430,31 @@ ct = gnutls_certificate_type_get(state->session); if (ct != GNUTLS_CRT_X509) { const char *ctn = gnutls_certificate_type_get_name(ct); - state->peerdn = string_sprintf("unknown (type %s)", ctn); DEBUG(D_tls) debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); - if (state->verify_requirement == VERIFY_REQUIRED) + if (state->verify_requirement >= VERIFY_REQUIRED) return tls_error(US"certificate verification not possible, unhandled type", - ctn, state->host); + ctn, state->host, errstr); return OK; } -#define exim_gnutls_peer_err(Label) do { \ - if (rc != GNUTLS_E_SUCCESS) { \ - DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \ - if (state->verify_requirement == VERIFY_REQUIRED) { return tls_error((Label), gnutls_strerror(rc), state->host); } \ - return OK; } } while (0) +#define exim_gnutls_peer_err(Label) \ + do { \ + if (rc != GNUTLS_E_SUCCESS) \ + { \ + DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ + (Label), gnutls_strerror(rc)); \ + if (state->verify_requirement >= VERIFY_REQUIRED) \ + return tls_error((Label), gnutls_strerror(rc), state->host, errstr); \ + return OK; \ + } \ + } while (0) + +rc = import_cert(&cert_list[0], &crt); +exim_gnutls_peer_err(US"cert 0"); -rc = gnutls_x509_crt_init(&crt); -exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)"); +state->tlsp->peercert = state->peercert = crt; -rc = gnutls_x509_crt_import(crt, &cert_list[0], GNUTLS_X509_FMT_DER); -exim_gnutls_peer_err(US"failed to import certificate [gnutls_x509_crt_import(cert 0)]"); sz = 0; rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) @@ -1051,6 +1465,7 @@ if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) dn_buf = store_get_perm(sz); rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); + state->peerdn = dn_buf; return OK; @@ -1071,7 +1486,7 @@ the peer information, but that's too new for some OSes. Arguments: state exim_gnutls_state_st * - error where to put an error message + errstr where to put an error message Returns: FALSE if the session should be rejected @@ -1079,52 +1494,76 @@ Returns: */ static BOOL -verify_certificate(exim_gnutls_state_st *state, const char **error) +verify_certificate(exim_gnutls_state_st *state, uschar ** errstr) { int rc; unsigned int verify; -*error = NULL; +*errstr = NULL; -rc = peer_status(state); -if (rc != OK) +if ((rc = peer_status(state, errstr)) != OK) { verify = GNUTLS_CERT_INVALID; - *error = "not supplied"; + *errstr = US"certificate not supplied"; } else - { rc = gnutls_certificate_verify_peers2(state->session, &verify); - } /* Handle the result of verification. INVALID seems to be set as well as REVOKED, but leave the test for both. */ -if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) +if (rc < 0 || + verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) + ) { state->peer_cert_verified = FALSE; - if (*error == NULL) - *error = ((verify & GNUTLS_CERT_REVOKED) != 0) ? "revoked" : "invalid"; + if (!*errstr) + *errstr = verify & GNUTLS_CERT_REVOKED + ? US"certificate revoked" : US"certificate invalid"; DEBUG(D_tls) - debug_printf("TLS certificate verification failed (%s): peerdn=%s\n", - *error, state->peerdn); + debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", + *errstr, state->peerdn ? state->peerdn : US""); - if (state->verify_requirement == VERIFY_REQUIRED) + if (state->verify_requirement >= VERIFY_REQUIRED) { - gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); + gnutls_alert_send(state->session, + GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); return FALSE; } DEBUG(D_tls) - debug_printf("TLS verify failure overriden (host in tls_try_verify_hosts)\n"); + debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); } + else { + if (state->exp_tls_verify_cert_hostnames) + { + int sep = 0; + const uschar * list = state->exp_tls_verify_cert_hostnames; + uschar * name; + while ((name = string_nextinlist(&list, &sep, NULL, 0))) + if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) + break; + if (!name) + { + DEBUG(D_tls) + debug_printf("TLS certificate verification failed: cert name mismatch\n"); + if (state->verify_requirement >= VERIFY_REQUIRED) + { + gnutls_alert_send(state->session, + GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); + return FALSE; + } + return TRUE; + } + } state->peer_cert_verified = TRUE; - DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", state->peerdn); + DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", + state->peerdn ? state->peerdn : US""); } -tls_peerdn = state->peerdn; +state->tlsp->peerdn = state->peerdn; return TRUE; } @@ -1143,7 +1582,14 @@ return TRUE; static void exim_gnutls_logger_cb(int level, const char *message) { - DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s\n", level, message); + size_t len = strlen(message); + if (len < 1) + { + DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); + return; + } + DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, + message[len-1] == '\n' ? "" : "\n"); } #endif @@ -1161,6 +1607,7 @@ handshake.". For inability to get SNI information, we return 0. We only return non-zero if re-setup failed. +Only used for server-side TLS. */ static int @@ -1168,9 +1615,10 @@ exim_sni_handling_cb(gnutls_session_t session) { char sni_name[MAX_HOST_LEN]; size_t data_len = MAX_HOST_LEN; -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = &state_server; unsigned int sni_type; int rc, old_pool; +uschar * dummy_errstr; rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); if (rc != GNUTLS_E_SUCCESS) @@ -1181,7 +1629,7 @@ if (rc != GNUTLS_E_SUCCESS) else debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", gnutls_strerror(rc), rc); - }; + } return 0; } @@ -1198,7 +1646,7 @@ state->received_sni = string_copyn(US sni_name, data_len); store_pool = old_pool; /* We set this one now so that variable expansions below will work */ -tls_sni = state->received_sni; +state->tlsp->sni = state->received_sni; DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, state->trigger_sni_changes ? "" : " (unused for certificate selection)"); @@ -1206,18 +1654,92 @@ DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, if (!state->trigger_sni_changes) return 0; -rc = tls_expand_session_files(state); -if (rc != OK) +if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) { /* If the setup of certs/etc failed before handshake, TLS would not have been offered. The best we can do now is abort. */ return GNUTLS_E_APPLICATION_ERROR_MIN; } -rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); -return (rc == GNUTLS_E_SUCCESS) ? 0 : rc; +rc = tls_set_remaining_x509(state, &dummy_errstr); +if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; + +return 0; +} + + + +#ifndef DISABLE_OCSP + +static int +server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, + gnutls_datum_t * ocsp_response) +{ +int ret; + +if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) + { + DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", + CS ptr); + tls_in.ocsp = OCSP_NOT_RESP; + return GNUTLS_E_NO_CERTIFICATE_STATUS; + } + +tls_in.ocsp = OCSP_VFY_NOT_TRIED; +return 0; } +#endif + + +#ifndef DISABLE_EVENT +/* +We use this callback to get observability and detail-level control +for an exim TLS connection (either direction), raising a tls:cert event +for each cert in the chain presented by the peer. Any event +can deny verification. + +Return 0 for the handshake to continue or non-zero to terminate. +*/ + +static int +verify_cb(gnutls_session_t session) +{ +const gnutls_datum_t * cert_list; +unsigned int cert_list_size = 0; +gnutls_x509_crt_t crt; +int rc; +uschar * yield; +exim_gnutls_state_st * state = gnutls_session_get_ptr(session); + +cert_list = gnutls_certificate_get_peers(session, &cert_list_size); +if (cert_list) + while (cert_list_size--) + { + rc = import_cert(&cert_list[cert_list_size], &crt); + if (rc != GNUTLS_E_SUCCESS) + { + DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", + cert_list_size, gnutls_strerror(rc)); + break; + } + + state->tlsp->peercert = crt; + if ((yield = event_raise(state->event_action, + US"tls:cert", string_sprintf("%d", cert_list_size)))) + { + log_write(0, LOG_MAIN, + "SSL verify denied by event-action: depth=%d: %s", + cert_list_size, yield); + return 1; /* reject */ + } + state->tlsp->peercert = NULL; + } + +return 0; +} + +#endif @@ -1237,27 +1759,25 @@ a TLS session. Arguments: require_ciphers list of allowed ciphers or NULL + errstr pointer to error string Returns: OK on success DEFER for errors before the start of the negotiation - FAIL for errors during the negotation; the server can't + FAIL for errors during the negotiation; the server can't continue running. */ int -tls_server_start(const uschar *require_ciphers) +tls_server_start(const uschar * require_ciphers, uschar ** errstr) { int rc; -const char *error; -exim_gnutls_state_st *state = NULL; +exim_gnutls_state_st * state = NULL; /* Check for previous activation */ -/* nb: this will not be TLS callout safe, needs reworking as part of that. */ - -if (tls_active >= 0) +if (tls_in.active >= 0) { - tls_error(US"STARTTLS received after TLS started", "", NULL); - smtp_printf("554 Already in TLS\r\n"); + tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); + smtp_printf("554 Already in TLS\r\n", FALSE); return FAIL; } @@ -1266,33 +1786,44 @@ and sent an SMTP response. */ DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); -rc = tls_init(NULL, tls_certificate, tls_privatekey, +if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, NULL, tls_verify_certificates, tls_crl, - require_ciphers, &state); -if (rc != OK) return rc; + require_ciphers, &state, errstr)) != OK) return rc; /* If this is a host for which certificate verification is mandatory or optional, set up appropriately. */ if (verify_check_host(&tls_verify_hosts) == OK) { - DEBUG(D_tls) debug_printf("TLS: a client certificate will be required.\n"); + DEBUG(D_tls) + debug_printf("TLS: a client certificate will be required.\n"); state->verify_requirement = VERIFY_REQUIRED; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); } else if (verify_check_host(&tls_try_verify_hosts) == OK) { - DEBUG(D_tls) debug_printf("TLS: a client certificate will be requested but not required.\n"); + DEBUG(D_tls) + debug_printf("TLS: a client certificate will be requested but not required.\n"); state->verify_requirement = VERIFY_OPTIONAL; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); } else { - DEBUG(D_tls) debug_printf("TLS: a client certificate will not be requested.\n"); + DEBUG(D_tls) + debug_printf("TLS: a client certificate will not be requested.\n"); state->verify_requirement = VERIFY_NONE; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); } +#ifndef DISABLE_EVENT +if (event_action) + { + state->event_action = event_action; + gnutls_session_set_ptr(state->session, state); + gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); + } +#endif + /* Register SNI handling; always, even if not in tls_certificate, so that the expansion variable $tls_sni is always available. */ @@ -1305,9 +1836,9 @@ make them disconnect. We need to have an explicit fflush() here, to force out the response. Other smtp_printf() calls do not need it, because in non-TLS mode, the fflush() happens when smtp_getc() is called. */ -if (!tls_on_connect) +if (!state->tlsp->on_connect) { - smtp_printf("220 TLS go ahead\r\n"); + smtp_printf("220 TLS go ahead\r\n", FALSE); fflush(smtp_out); } @@ -1315,31 +1846,41 @@ if (!tls_on_connect) that the GnuTLS library doesn't. */ gnutls_transport_set_ptr2(state->session, - (gnutls_transport_ptr)fileno(smtp_in), - (gnutls_transport_ptr)fileno(smtp_out)); + (gnutls_transport_ptr_t)(long) fileno(smtp_in), + (gnutls_transport_ptr_t)(long) fileno(smtp_out)); state->fd_in = fileno(smtp_in); state->fd_out = fileno(smtp_out); sigalrm_seen = FALSE; if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); do - { rc = gnutls_handshake(state->session); - } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED)); +while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); alarm(0); if (rc != GNUTLS_E_SUCCESS) { - tls_error(US"gnutls_handshake", - sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); /* It seems that, except in the case of a timeout, we have to close the connection right here; otherwise if the other end is running OpenSSL it hangs until the server times out. */ - if (!sigalrm_seen) + if (sigalrm_seen) { + tls_error(US"gnutls_handshake", "timed out", NULL, errstr); + gnutls_db_remove_session(state->session); + } + else + { + tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL, errstr); + (void) gnutls_alert_send_appropriate(state->session, rc); + gnutls_deinit(state->session); + gnutls_certificate_free_credentials(state->x509_cred); + millisleep(500); + shutdown(state->fd_out, SHUT_WR); + for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ (void)fclose(smtp_out); (void)fclose(smtp_in); + smtp_out = smtp_in = NULL; } return FAIL; @@ -1349,28 +1890,22 @@ DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); /* Verify after the fact */ -if (state->verify_requirement != VERIFY_NONE) +if ( state->verify_requirement != VERIFY_NONE + && !verify_certificate(state, errstr)) { - if (!verify_certificate(state, &error)) + if (state->verify_requirement != VERIFY_OPTIONAL) { - if (state->verify_requirement == VERIFY_OPTIONAL) - { - DEBUG(D_tls) - debug_printf("TLS: continuing on only because verification was optional, after: %s\n", - error); - } - else - { - tls_error(US"certificate verification failed", error, NULL); - return FAIL; - } + (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); + return FAIL; } + DEBUG(D_tls) + debug_printf("TLS: continuing on only because verification was optional, after: %s\n", + *errstr); } /* Figure out peer DN, and if authenticated, etc. */ -rc = peer_status(state); -if (rc != OK) return rc; +if ((rc = peer_status(state, NULL)) != OK) return rc; /* Sets various Exim expansion variables; always safe within server */ @@ -1382,6 +1917,8 @@ and initialize appropriately. */ state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); receive_getc = tls_getc; +receive_getbuf = tls_getbuf; +receive_get_cache = tls_get_cache; receive_ungetc = tls_ungetc; receive_feof = tls_feof; receive_ferror = tls_ferror; @@ -1393,6 +1930,25 @@ return OK; +static void +tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, + smtp_transport_options_block * ob) +{ +if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) + { + state->exp_tls_verify_cert_hostnames = +#ifdef SUPPORT_I18N + string_domain_utf8_to_alabel(host->name, NULL); +#else + host->name; +#endif + DEBUG(D_tls) + debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", + state->exp_tls_verify_cert_hostnames); + } +} + + /************************************************* * Start a TLS session in a client * *************************************************/ @@ -1403,14 +1959,9 @@ Arguments: fd the fd of the connection host connected host (for messages) addr the first address (not used) - dhparam DH parameter file (ignored, we're a client) - certificate certificate file - privatekey private key file - sni TLS SNI to send to remote host - verify_certs file for certificate verify - verify_crl CRL for verify - require_ciphers list of allowed ciphers or NULL - timeout startup timeout + tb transport (always smtp) + + errstr error string pointer Returns: OK/DEFER/FAIL (because using common functions), but for a client, DEFER and FAIL have the same meaning @@ -1418,65 +1969,173 @@ Returns: OK/DEFER/FAIL (because using common functions), int tls_client_start(int fd, host_item *host, - address_item *addr ARG_UNUSED, uschar *dhparam ARG_UNUSED, - uschar *certificate, uschar *privatekey, uschar *sni, - uschar *verify_certs, uschar *verify_crl, - uschar *require_ciphers, int timeout) + address_item *addr ARG_UNUSED, + transport_instance * tb, +#ifdef EXPERIMENTAL_DANE + dns_answer * tlsa_dnsa ARG_UNUSED, +#endif + uschar ** errstr) { +smtp_transport_options_block *ob = + (smtp_transport_options_block *)tb->options_block; int rc; -const char *error; exim_gnutls_state_st *state = NULL; +#ifndef DISABLE_OCSP +BOOL require_ocsp = + verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; +BOOL request_ocsp = require_ocsp ? TRUE + : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; +#endif DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); -rc = tls_init(host, certificate, privatekey, - sni, verify_certs, verify_crl, require_ciphers, &state); -if (rc != OK) return rc; +if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, + ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, + ob->tls_require_ciphers, &state, errstr)) != OK) + return rc; -gnutls_dh_set_prime_bits(state->session, EXIM_CLIENT_DH_MIN_BITS); + { + int dh_min_bits = ob->tls_dh_min_bits; + if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) + { + DEBUG(D_tls) + debug_printf("WARNING: tls_dh_min_bits far too low," + " clamping %d up to %d\n", + dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); + dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; + } + + DEBUG(D_tls) debug_printf("Setting D-H prime minimum" + " acceptable bits to %d\n", + dh_min_bits); + gnutls_dh_set_prime_bits(state->session, dh_min_bits); + } + +/* Stick to the old behaviour for compatibility if tls_verify_certificates is +set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only +the specified host patterns if one of them is defined */ -if (verify_certs == NULL) +if ( ( state->exp_tls_verify_certificates + && !ob->tls_verify_hosts + && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) + ) + || verify_check_given_host(&ob->tls_verify_hosts, host) == OK + ) { - DEBUG(D_tls) debug_printf("TLS: server certificate verification not required\n"); - state->verify_requirement = VERIFY_NONE; - /* we still ask for it, to log it, etc */ + tls_client_setup_hostname_checks(host, state, ob); + DEBUG(D_tls) + debug_printf("TLS: server certificate verification required.\n"); + state->verify_requirement = VERIFY_REQUIRED; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); + } +else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) + { + tls_client_setup_hostname_checks(host, state, ob); + DEBUG(D_tls) + debug_printf("TLS: server certificate verification optional.\n"); + state->verify_requirement = VERIFY_OPTIONAL; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); } else { - DEBUG(D_tls) debug_printf("TLS: server certificate verification required\n"); - state->verify_requirement = VERIFY_REQUIRED; - gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); + DEBUG(D_tls) + debug_printf("TLS: server certificate verification not required.\n"); + state->verify_requirement = VERIFY_NONE; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); } -gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)fd); +#ifndef DISABLE_OCSP + /* supported since GnuTLS 3.1.3 */ +if (request_ocsp) + { + DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); + if ((rc = gnutls_ocsp_status_request_enable_client(state->session, + NULL, 0, NULL)) != OK) + return tls_error(US"cert-status-req", + gnutls_strerror(rc), state->host, errstr); + tls_out.ocsp = OCSP_NOT_RESP; + } +#endif + +#ifndef DISABLE_EVENT +if (tb->event_action) + { + state->event_action = tb->event_action; + gnutls_session_set_ptr(state->session, state); + gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); + } +#endif + +gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); state->fd_in = fd; state->fd_out = fd; +DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); /* There doesn't seem to be a built-in timeout on connection. */ sigalrm_seen = FALSE; -alarm(timeout); +alarm(ob->command_timeout); do { rc = gnutls_handshake(state->session); - } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED)); + } while ((rc == GNUTLS_E_AGAIN) || + (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); alarm(0); +if (rc != GNUTLS_E_SUCCESS) + if (sigalrm_seen) + { + gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); + return tls_error(US"gnutls_handshake", "timed out", state->host, errstr); + } + else + return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); + DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); /* Verify late */ if (state->verify_requirement != VERIFY_NONE && - !verify_certificate(state, &error)) - return tls_error(US"certificate verification failed", error, state->host); + !verify_certificate(state, errstr)) + return tls_error(US"certificate verification failed", *errstr, state->host, errstr); + +#ifndef DISABLE_OCSP +if (require_ocsp) + { + DEBUG(D_tls) + { + gnutls_datum_t stapling; + gnutls_ocsp_resp_t resp; + gnutls_datum_t printed; + if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 + && (rc= gnutls_ocsp_resp_init(&resp)) == 0 + && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 + && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 + ) + { + debug_printf("%.4096s", printed.data); + gnutls_free(printed.data); + } + else + (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host, errstr); + } + + if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) + { + tls_out.ocsp = OCSP_FAILED; + return tls_error(US"certificate status check failed", NULL, state->host, errstr); + } + DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); + tls_out.ocsp = OCSP_VFIED; + } +#endif /* Figure out peer DN, and if authenticated, etc. */ -rc = peer_status(state); -if (rc != OK) return rc; +if ((rc = peer_status(state, errstr)) != OK) + return rc; -/* Sets various Exim expansion variables; always safe within server */ +/* Sets various Exim expansion variables; may need to adjust for ACL callouts */ extract_exim_vars_from_tls_state(state); @@ -1499,11 +2158,11 @@ Returns: nothing */ void -tls_close(BOOL shutdown) +tls_close(BOOL is_server, BOOL shutdown) { -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = is_server ? &state_server : &state_client; -if (tls_active < 0) return; /* TLS was not active */ +if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ if (shutdown) { @@ -1512,7 +2171,10 @@ if (shutdown) } gnutls_deinit(state->session); +gnutls_certificate_free_credentials(state->x509_cred); + +state->tlsp->active = -1; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); if ((state_server.session == NULL) && (state_client.session == NULL)) @@ -1520,86 +2182,149 @@ if ((state_server.session == NULL) && (state_client.session == NULL)) gnutls_global_deinit(); exim_gnutls_base_init_done = FALSE; } - -tls_active = -1; } +static BOOL +tls_refill(unsigned lim) +{ +exim_gnutls_state_st * state = &state_server; +ssize_t inbytes; + +DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", + state->session, state->xfer_buffer, ssl_xfer_buffer_size); + +if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); +inbytes = gnutls_record_recv(state->session, state->xfer_buffer, + MIN(ssl_xfer_buffer_size, lim)); +alarm(0); + +/* Timeouts do not get this far; see command_timeout_handler(). + A zero-byte return appears to mean that the TLS session has been + closed down, not that the socket itself has been closed down. Revert to + non-TLS handling. */ + +if (sigalrm_seen) + { + DEBUG(D_tls) debug_printf("Got tls read timeout\n"); + state->xfer_error = 1; + return FALSE; + } + +else if (inbytes == 0) + { + DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); + + receive_getc = smtp_getc; + receive_getbuf = smtp_getbuf; + receive_get_cache = smtp_get_cache; + receive_ungetc = smtp_ungetc; + receive_feof = smtp_feof; + receive_ferror = smtp_ferror; + receive_smtp_buffered = smtp_buffered; + + gnutls_deinit(state->session); + gnutls_certificate_free_credentials(state->x509_cred); + + state->session = NULL; + state->tlsp->active = -1; + state->tlsp->bits = 0; + state->tlsp->certificate_verified = FALSE; + tls_channelbinding_b64 = NULL; + state->tlsp->cipher = NULL; + state->tlsp->peercert = NULL; + state->tlsp->peerdn = NULL; + + return FALSE; + } + +/* Handle genuine errors */ + +else if (inbytes < 0) + { + record_io_error(state, (int) inbytes, US"recv", NULL); + state->xfer_error = 1; + return FALSE; + } +#ifndef DISABLE_DKIM +dkim_exim_verify_feed(state->xfer_buffer, inbytes); +#endif +state->xfer_buffer_hwm = (int) inbytes; +state->xfer_buffer_lwm = 0; +return TRUE; +} + /************************************************* * TLS version of getc * *************************************************/ /* This gets the next byte from the TLS input buffer. If the buffer is empty, it refills the buffer via the GnuTLS reading function. +Only used by the server-side TLS. This feeds DKIM and should be used for all message-body reads. -Arguments: none +Arguments: lim Maximum amount to read/bufffer Returns: the next character or EOF */ int -tls_getc(void) +tls_getc(unsigned lim) { -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st * state = &state_server; + if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) - { - ssize_t inbytes; + if (!tls_refill(lim)) + return state->xfer_error ? EOF : smtp_getc(lim); - DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", - state->session, state->xfer_buffer, ssl_xfer_buffer_size); +/* Something in the buffer; return next uschar */ - if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); - inbytes = gnutls_record_recv(state->session, state->xfer_buffer, - ssl_xfer_buffer_size); - alarm(0); +return state->xfer_buffer[state->xfer_buffer_lwm++]; +} - /* A zero-byte return appears to mean that the TLS session has been - closed down, not that the socket itself has been closed down. Revert to - non-TLS handling. */ +uschar * +tls_getbuf(unsigned * len) +{ +exim_gnutls_state_st * state = &state_server; +unsigned size; +uschar * buf; - if (inbytes == 0) +if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) + if (!tls_refill(*len)) { - DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); - - receive_getc = smtp_getc; - receive_ungetc = smtp_ungetc; - receive_feof = smtp_feof; - receive_ferror = smtp_ferror; - receive_smtp_buffered = smtp_buffered; - - gnutls_deinit(state->session); - state->session = NULL; - tls_active = -1; - tls_bits = 0; - tls_certificate_verified = FALSE; - tls_channelbinding_b64 = NULL; - tls_cipher = NULL; - tls_peerdn = NULL; - - return smtp_getc(); + if (!state->xfer_error) return smtp_getbuf(len); + *len = 0; + return NULL; } - /* Handle genuine errors */ +if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) + size = *len; +buf = &state->xfer_buffer[state->xfer_buffer_lwm]; +state->xfer_buffer_lwm += size; +*len = size; +return buf; +} - else if (inbytes < 0) - { - record_io_error(state, (int) inbytes, US"recv", NULL); - state->xfer_error = 1; - return EOF; - } + +void +tls_get_cache() +{ #ifndef DISABLE_DKIM - dkim_exim_verify_feed(state->xfer_buffer, inbytes); +exim_gnutls_state_st * state = &state_server; +int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; +if (n > 0) + dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); #endif - state->xfer_buffer_hwm = (int) inbytes; - state->xfer_buffer_lwm = 0; - } +} -/* Something in the buffer; return next uschar */ -return state->xfer_buffer[state->xfer_buffer_lwm++]; +BOOL +tls_could_read(void) +{ +return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm + || gnutls_record_check_pending(state_server.session) > 0; } @@ -1611,6 +2336,7 @@ return state->xfer_buffer[state->xfer_buffer_lwm++]; /* This does not feed DKIM, so if the caller uses this for reading message body, then the caller must feed DKIM. + Arguments: buff buffer of data len size of buffer @@ -1620,9 +2346,9 @@ Returns: the number of bytes read */ int -tls_read(uschar *buff, size_t len) +tls_read(BOOL is_server, uschar *buff, size_t len) { -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = is_server ? &state_server : &state_client; ssize_t inbytes; if (len > INT_MAX) @@ -1658,21 +2384,30 @@ return -1; /* Arguments: + is_server channel specifier buff buffer of data len number of bytes + more more data expected soon Returns: the number of bytes after a successful write, -1 after a failed write */ int -tls_write(const uschar *buff, size_t len) +tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) { ssize_t outbytes; size_t left = len; -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = is_server ? &state_server : &state_client; +#ifdef SUPPORT_CORK +static BOOL corked = FALSE; + +if (more && !corked) gnutls_record_cork(state->session); +#endif + +DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, + buff, left, more ? ", more" : ""); -DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); while (left > 0) { DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", @@ -1703,6 +2438,14 @@ if (len > INT_MAX) len = INT_MAX; } +#ifdef SUPPORT_CORK +if (more != corked) + { + if (!more) (void) gnutls_record_uncork(state->session, 0); + corked = more; + } +#endif + return (int) len; } @@ -1773,6 +2516,73 @@ vaguely_random_number(int max) +/************************************************* +* Let tls_require_ciphers be checked at startup * +*************************************************/ + +/* The tls_require_ciphers option, if set, must be something which the +library can parse. + +Returns: NULL on success, or error message +*/ + +uschar * +tls_validate_require_cipher(void) +{ +int rc; +uschar *expciphers = NULL; +gnutls_priority_t priority_cache; +const char *errpos; +uschar * dummy_errstr; + +#define validate_check_rc(Label) do { \ + if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ + return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) +#define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) + +if (exim_gnutls_base_init_done) + log_write(0, LOG_MAIN|LOG_PANIC, + "already initialised GnuTLS, Exim developer bug"); + +#ifdef HAVE_GNUTLS_PKCS11 +if (!gnutls_allow_auto_pkcs11) + { + rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); + validate_check_rc(US"gnutls_pkcs11_init"); + } +#endif +rc = gnutls_global_init(); +validate_check_rc(US"gnutls_global_init()"); +exim_gnutls_base_init_done = TRUE; + +if (!(tls_require_ciphers && *tls_require_ciphers)) + return_deinit(NULL); + +if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, + &dummy_errstr)) + return_deinit(US"failed to expand tls_require_ciphers"); + +if (!(expciphers && *expciphers)) + return_deinit(NULL); + +DEBUG(D_tls) + debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); + +rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); +validate_check_rc(string_sprintf( + "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", + expciphers, errpos - CS expciphers, errpos)); + +#undef return_deinit +#undef validate_check_rc +gnutls_global_deinit(); + +return NULL; +} + + + + /************************************************* * Report the library versions. * *************************************************/ @@ -1792,4 +2602,6 @@ fprintf(f, "Library version: GnuTLS: Compile: %s\n" gnutls_check_version(NULL)); } +/* vi: aw ai sw=2 +*/ /* End of tls-gnu.c */